You have a Microsoft Teams Phone deployment. You have a PBX that connects to the PSTN by using an E1/T1 Primary Rate interface (PRI). You plan to migrate to Direct Routing by using the existing PSTN s

Question

Options

• Aa physical Session Border Controller (SBC)
• Ban FXO SIP Analog Telephony Adapter (ATA)
• Ca virtual Session Border Controller (SBC)
• Da Session Border Controller (SBC) in Azure

• A
  93% (14)
• B
  7% (1)

Explanation

Direct Routing requires a certified Session Border Controller (SBC) to sit between Teams and your PSTN or PBX infrastructure. In this scenario, the existing PBX uses E1/T1 PRI - a physical TDM (Time Division Multiplexing) interface - to connect to the PSTN. A physical SBC (A) is required because it must have physical E1/T1 ports to terminate the PRI connection from the carrier side, while presenting a SIP interface toward Teams on the other side. Virtual SBCs (C) and Azure-hosted SBCs (D) are software-based and do not have physical hardware ports for TDM connections like E1/T1 PRI. An FXO ATA (B) is designed to bridge analog telephone lines (FXO), not E1/T1 PRI digital circuits. Therefore, only a physical SBC can bridge the TDM PRI to SIP for Teams Direct Routing.

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